feat: 记住上次选中的配置，下次启动自动选中

- 启用 AppConfig.DefaultProfileID 字段（此前声明但未使用）
- 启动时 loadProfiles() 优先选中上次记录的配置，找不到则回退到第一个
- 切换配置时立即持久化到 config.yml，防止崩溃丢失
- 使用 Profile ID 而非名称，避免重命名后失效

Makefile

@@ -11,7 +11,7 @@ GO          = go
 CGO_ENABLED = 1
 WINDRES     ?= x86_64-w64-mingw32-windres
 MINGW_CC    ?= x86_64-w64-mingw32-gcc
-SEMVER      ?= 0.4.2
+SEMVER      ?= 0.4.3
 GIT_HASH    = $(shell git rev-parse --short HEAD 2>/dev/null || echo unknown)
 VERSION     = $(SEMVER)-$(GIT_HASH)
 LDFLAGS     = -s -w -X lmvpn/internal/version.Version=$(VERSION)

internal/ui/app.go

@@ -48,11 +48,12 @@ type App struct {
 	disconnectBtn *widget.Button
 
 	// State
-	mu             sync.Mutex
-	ipcClient      *ipc.Client
-	profiles       []model.ServerProfile
-	currentProfile *model.ServerProfile
-	langSetting    string
+	mu              sync.Mutex
+	ipcClient       *ipc.Client
+	profiles        []model.ServerProfile
+	currentProfile  *model.ServerProfile
+	defaultProfileID int64
+	langSetting     string
 }
 
 // Run initialises and starts the GUI application.
@@ -84,6 +85,7 @@ func Run() {
 		db:                store,
 		kc:                keychain.New(),
 		langSetting:       cfg.Language,
+		defaultProfileID:  cfg.DefaultProfileID,
 		listSelectedIndex: -1,
 	}
 
@@ -144,8 +146,21 @@ func (a *App) loadProfiles() {
 	names := a.profileNames()
 	a.profileSelect.Options = names
 	if len(names) > 0 {
-		a.profileSelect.SetSelectedIndex(0)
-		a.selectProfileByName(names[0])
+		selected := false
+		if a.defaultProfileID > 0 {
+			for i := range a.profiles {
+				if a.profiles[i].ID == a.defaultProfileID {
+					a.profileSelect.SetSelectedIndex(i)
+					a.selectProfileByName(a.profiles[i].Name)
+					selected = true
+					break
+				}
+			}
+		}
+		if !selected {
+			a.profileSelect.SetSelectedIndex(0)
+			a.selectProfileByName(names[0])
+		}
 	} else {
 		a.currentProfile = nil
 		a.profileSelect.SetSelected("")
@@ -182,6 +197,26 @@ func (a *App) selectProfileByName(name string) {
 	}
 }
 
+// saveDefaultProfile persists the currently selected profile ID to the
+// config file so it can be restored on the next launch.
+func (a *App) saveDefaultProfile() {
+	if a.currentProfile == nil {
+		return
+	}
+	a.defaultProfileID = a.currentProfile.ID
+	cfg, err := config.Load()
+	if err != nil {
+		cfg = config.Default()
+	}
+	if cfg.DefaultProfileID == a.currentProfile.ID {
+		return
+	}
+	cfg.DefaultProfileID = a.currentProfile.ID
+	if err := config.Save(cfg); err != nil {
+		log.L().Error("save default profile", "error", err)
+	}
+}
+
 // onAddProfile shows a dialog to create a new profile.
 func (a *App) onAddProfile() {
 	a.showProfileDialog(nil)

internal/ui/view.go

@@ -54,6 +54,7 @@ func (a *App) buildMainWindow() fyne.CanvasObject {
 	// Profile selector.
 	a.profileSelect = widget.NewSelect(a.profileNames(), func(sel string) {
 		a.selectProfileByName(sel)
+		a.saveDefaultProfile()
 	})
 
 	// Status display.